Wireless neurostimulators

Abstract

A neurostimulator implant includes an insulating member and an elongate circuitry unit. The circuitry unit includes (a) a first electrode, disposed on an outer surface of a first end portion of the circuitry unit; (b) a second electrode, disposed on an outer surface of a second end portion of the circuitry unit; and (c) circuitry, disposed inside the circuitry unit, and configured to be wirelessly powered to drive an electrical current between the first and second electrodes. The circuitry unit is disposed alongside a medial part of the insulating member, bulging away from the insulating member to define a generally arced portion of the implant. Lateral parts of the insulating member extend laterally outward from the medial part to define lateral zones laterally beyond the circuitry unit. The second side of the insulating member defines a generally flat side of the implant. Other embodiments are also described.

The invention claimed is: 
     
       1. Apparatus configured for use with tissue of a subject, the apparatus comprising a neurostimulator implant, the implant comprising:
 an insulating member having a first side and a second side; and 
 an elongate circuitry unit:
 (a) having a first end portion and a second end portion, and defining a longitudinal axis therebetween, 
 (b) comprising:
 a first electrode, disposed on an outer surface of the circuitry unit at the first end portion; 
 a second electrode, disposed on the outer surface of the circuitry unit at the second end portion; and 
 circuitry, disposed inside the circuitry unit, and configured to be wirelessly powered to drive an electrical current between the first and second electrodes, and 
 
 (c) coupled to a medial part of the insulating member, such that:
 the circuitry unit is disposed alongside the medial part of the insulating member, on the first side of the insulating member, bulging away from insulating member to define a generally arced portion of the implant, and is configured to facilitate conduction of the electrical current in a first direction away from the generally arced portion of the implant, 
 lateral parts of the insulating member extend laterally outward from the medial part to define lateral zones extending laterally beyond edges of the circuitry unit, wherein there are no electrodes of the implant disposed in the lateral zones, and 
 the second side of the insulating member defines a generally flat side of the implant, facing a second direction opposite the first direction and away from the generally arced portion of the implant and the first and second electrodes of the circuitry unit. 
 
 
 
     
     
       2. The apparatus according to  claim 1 , wherein the first electrode is disposed on the outer surface of the circuitry unit such that the first electrode extends around the arced portion of the implant at the first end portion, and the second electrode is disposed on the outer surface of the circuitry unit such that the second electrode extends around the arced portion of the implant at the second end portion. 
     
     
       3. The apparatus according to  claim 1 , wherein the insulating member comprises insulating silicone. 
     
     
       4. The apparatus according to  claim 1 , wherein the insulating member inhibits conduction of the electrical current away from the implant in the second direction. 
     
     
       5. The apparatus according to  claim 1 , wherein the implant is configured to be implanted in a limb of the subject. 
     
     
       6. The apparatus according to  claim 1 , wherein the circuitry is configured to configure the electrical current to have a frequency of 10-40 Hz. 
     
     
       7. The apparatus according to  claim 1 , wherein (a) the implant does not comprise a power supply, or (b) the implant comprises a power supply that is not able to continuously power the implant for a period greater than one minute. 
     
     
       8. The apparatus according to  claim 1 , wherein the implant is configured such that the driving of the electrical current does not induce contraction of a muscle of the subject. 
     
     
       9. The apparatus according to  claim 1 , wherein the circuitry is configured to configure the electrical current to stimulate a tibial nerve. 
     
     
       10. The apparatus according to  claim 9 , wherein the circuitry is configured to configure the electrical current to induce paresthesia. 
     
     
       11. The apparatus according to  claim 9 , wherein the circuitry is configured to configure the electrical current to treat neuropathic pain. 
     
     
       12. The apparatus according to  claim 1 , wherein the circuitry unit has a length, from a first end thereof to a second end thereof, of 5-50 mm. 
     
     
       13. The apparatus according to  claim 12 , wherein the length of the circuitry unit is 10-30 mm. 
     
     
       14. The apparatus according to  claim 12 , wherein the circuitry unit is 1-5 mm in width. 
     
     
       15. The apparatus according to  claim 14 , wherein the circuitry unit is 1.5-3 mm in width. 
     
     
       16. The apparatus according to  claim 1 , wherein each of the lateral zones extends greater than 1 mm laterally beyond the circuitry unit. 
     
     
       17. The apparatus according to  claim 16 , wherein each of the lateral zones extends greater than 2 mm laterally beyond the circuitry unit. 
     
     
       18. The apparatus according to  claim 17 , wherein each of the lateral zones extends greater than 5 mm laterally beyond the circuitry unit. 
     
     
       19. The apparatus according to  claim 1 , further comprising a transmitting unit, configured to transmit wireless power, and wherein the circuitry is configured to be wirelessly powered, by the wireless power, to drive the electrical current between the first and second electrodes. 
     
     
       20. The apparatus according to  claim 19 , wherein the transmitting unit is configured to be wearable by the subject. 
     
     
       21. The apparatus according to  claim 19 , wherein the circuitry is configured to apply the electrical current only when the implant receives the wireless power.